/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#include <thrift/thrift-config.h>

#include <thrift/concurrency/ThreadFactory.h>
#include <thrift/concurrency/Exception.h>

#include <cassert>

#include <boost/weak_ptr.hpp>
#include <boost/thread.hpp>

namespace apache {
namespace thrift {
namespace concurrency {

using boost::shared_ptr;
using boost::weak_ptr;

/**
 * The boost thread class.
 *
 * @version $Id:$
 */
class BoostThread : public Thread
{
public:
  enum STATE {
    uninitialized,
    starting,
    started,
    stopping,
    stopped
  };

  static void* threadMain(void* arg);

private:
  std::auto_ptr<boost::thread> thread_;
  STATE state_;
  weak_ptr<BoostThread> self_;
  bool detached_;

public:
  BoostThread(bool detached, const shared_ptr<Runnable>& runnable)
    : state_(uninitialized)
    , detached_(detached)
  {
    this->Thread::runnable(runnable);
  }

  ~BoostThread()
  {
    if (!detached_)
    {
      try {
        join();
      }
      catch (...) {
        // We're really hosed.
      }
    }
  }

  void start()
  {
    if (state_ != uninitialized) {
      return;
    }

    // Create reference
    shared_ptr<BoostThread>* selfRef = new shared_ptr<BoostThread>();
    *selfRef = self_.lock();

    state_ = starting;

    thread_ = std::auto_ptr<boost::thread>(new boost::thread(boost::bind(threadMain, (void*)selfRef)));

    if (detached_)
      thread_->detach();
  }

  void join()
  {
    if (!detached_ && state_ != uninitialized) {
      thread_->join();
    }
  }

  Thread::id_t getId()
  { 
    return thread_.get() ? thread_->get_id() : boost::thread::id();
  }

  shared_ptr<Runnable> runnable() const
  {
    return Thread::runnable();
  }

  void runnable(const shared_ptr<Runnable>& value)
  { 
    Thread::runnable(value);
  }

  void weakRef(const shared_ptr<BoostThread>& self)
  {
    assert(self.get() == this);
    self_ = weak_ptr<BoostThread>(self);
  }
};

void* BoostThread::threadMain(void* arg)
{
  shared_ptr<BoostThread> thread = *(shared_ptr<BoostThread>*)arg;
  delete reinterpret_cast<shared_ptr<BoostThread>*>(arg);

  if (!thread) {
    return (void*)0;
  }

  if (thread->state_ != starting) {
    return (void*)0;
  }

  thread->state_ = started;
  thread->runnable()->run();

  if (thread->state_ != stopping && thread->state_ != stopped) {
    thread->state_ = stopping;
  }
  return (void*)0;
}

/**
 * boost thread factory implementation
 */
class ThreadFactory::Impl
{
private:
  bool detached_;

public:
  Impl(bool detached)
    : detached_(detached)
  {
  
  }

  /**
   * Creates a new boost thread to run the runnable object
   *
   * @param runnable A runnable object
   */
  shared_ptr<Thread> newThread(const shared_ptr<Runnable>& runnable) const
  {
    shared_ptr<BoostThread> result(new BoostThread(detached_, runnable));
    result->weakRef(result);
    runnable->thread(result);
    return result;
  }

  bool isDetached() const
  {
    return detached_;
  }

  void setDetached(bool value)
  {
    detached_ = value;
  }

  Thread::id_t getCurrentThreadId() const
  { 
    return boost::this_thread::get_id();
  }
};

ThreadFactory::ThreadFactory(bool detached)
  : impl_(new ThreadFactory::Impl(detached))
{

}

shared_ptr<Thread> ThreadFactory::newThread(const shared_ptr<Runnable>& runnable) const
{
  return impl_->newThread(runnable);
}

bool ThreadFactory::isDetached() const
{
  return impl_->isDetached();
}

void ThreadFactory::setDetached(bool value)
{
  impl_->setDetached(value);
}

Thread::id_t ThreadFactory::getCurrentThreadId() const
{
  return impl_->getCurrentThreadId();
}

}
}
} // apache::thrift::concurrency
